Prosecutors dropped the charges against Nancy Styler on Tuesday and against Carpenter on Friday. Caloia said Friday that William Styler had told authorities he acted alone in the slaying.

At sentencing, Pfister's relatives asked Chief District Judge James Boyd to impose a maximum sentence of 32 years for the second-degree murder charge. Prosecutors recommended a 20-year term in a prison with medical facilities, and Boyd agreed.

Styler had appeared in court in a wheelchair for an unspecified health condition.

"We do believe that this is a good and just resolution to these cases and hope that Nancy Pfister's family can find peace in knowing what happened," said a statement issued by Caloia's office.

Citing Styler's age and health, it added, "We believe this will be a life sentence for him."